Building track car need advice
 

Right now we are about done with our lemons car (which reminds me to update the other post about that), and now i really want to build up a track only car. I need some input about what i am going to do. The build is going to be on a budget of about $7,000. Here are the specs i am looking at:

*= already have and cost

Car/Drivetrain
95 Miata body stripped completely inside. *$1200
95 5-speed * came with 95 with car
Torsen Type I *$400
Autopower Roll Cage *$250

Suspension
Tein Flex With 9/7 Springs *$1500
Energy bushings a arm *$180
Energy Diff bushings *$67
Racing beat hollow front
Stock 14" wheels for now
Hankook RS2


Motor/Power
99 Motor *$750
T25 Turbo (wanted to stay small) *125
JGS Manifold welded myself
DIY Downpipe with mandrel pieces
Ebay intercooler
DIY intercooler pipes
2.5" straight pipe exhaust
Bigger Clutch (maybe new fm kit?)

Brakes
New Rotors
Carbotech pads (but which ones?)

Engine management
Megasquirt II w/ITA
Knocksense (maybe?)
EBC

So total for what i have spent is only $4472 and i still haven't sold anything yet from the car. I am thinking about going with the wing from 949, which would be about anoth $750 or so. What sugestions can you guys make for me? Turbo is pretty much a journal bearing GT25R from a nissan SR20DET, that i bought in great condidtion for next to nothing. This isn't my first rodeo, but i'm not arrogant enough to say i know exactly what i need.

Hankook has discontinued the RS2 and replaced it with an improved tire called the RS3. it has a lower tread wear rating = better grip = shorter life.

I got bored today and browsed the Targe website, I really want to copy what they did body wise, I think it looks like what a race car should. Also maybe focus on aerodynamics?

yeah i am probably going to strip it down like what they did with the targa and do some seem welds and give it a cheap decent paint job. On the outside it will be painted black and look alot like Savington's car.

Need: Seat, fire bottle, harnesses, radiator, oilcooler, towhooks, seat back brace, WBO2.

Nice to have: End links, hard top, 6uls with NT01s, wings and things, removable steering wheel, EGT.


About the carbotechs do a search, it was discussed recently.

Seat: Sparco sprint or ultrashield
Fire Bottle: Have it. Didn't list it.
Radiator: 55mm PWR
Oil cooler: Cooler and Mocal Thermostat
Tow Hooks: Didn't think of that because the stock ones are up in there and kind of small.
Seat back brace: I will have to do some searhcing on this. I'm pretty sure i can make a guess as to what it is, but as to where i get it from and functionality, i need more info.
WB: LC-1 gauge kit with the new digital gauges

With the brakes, everthing i have seen is a little different. I have done searching on it, but haven't really come up with a definative answer. the XP12 in the front and XP10 in the rears seemed like a good match to me for about 180hp.

R-S3 is not available in 14" diameter. See Welcome To Hankook Tire

Tire Rack still has 14" Ventus R-S2's in stock.

I will be getting some of the newer 6ULR when those come out so hopefully i can last until then on a couple sets of RS2 that online tires has let.

you'll definitely need the radiator and oil cooler. Make sure you have good t-bolt clamps on the intercooler pipes and keep the routing as simple as possible. Also consider bead rolling the intercooler pipes. You'll need to beef up your pcv system too, oil goes all sorts of places with the higher G's of racing. Definitely a hardtop and some type of vents into the driver, I've found that even with the windows down going 100mph+ it doesn't much air to me. Heat and vibration are your enemies, prioritize bullet proofing your chassis and drivetrain over power and aerodynamics.

With a dedicated track car, how advisable is it to have knocksense?

Also i am thinking of FM frame rails.

doesn't sound like a bad idea. Something else I saw on the Targa car that I thought was cool was running both the 1.6 and 1.8 oil pressure sensor. Since the 1.8 only verifies that there is 7 psi of oil pressure, it would trip a warning light when the pressure dropped below this value.

However all this track talk has me wondering if our cars would benefit from a dry sump system? I suppose not with the squirters down there.

rharris make sure to take lots'o'pictures

get in line.

What tracks will you run on and how competitive do you need to be.
The wing will help with all sorts of cornering, but be a hindrance to top-speed... which might be important unless you want to get passed down every straight. Of course on smaller tracks, top-speed won't be so much of a factor.

With the SR20det T25 and a 1.8 on MS, you can expect in the 220whp range with the 2.5" exhaust on a good tune with 93octane. You can run some more timing on race-gas, but don't get your hopes up for more than 230whp at around 15psi... and that's on a great tune. Don't forget injectors... and I'd skip the Knocksense and just run good gas and don't get crazy with the timing.

I think your choice of R&P will be important. If you plan to run a 4.3dif, expect to spend a shit-ton of time shifting and running in 5th gear a lot (again, depending on the track). I think 4th on my 5spd/4.3 was good for about 92mph. I don't think you've got the power for a 3.636 but a 4.1 or 3.9 might be huge for you.

And because of the recent interest in the topic, don't forget one of those kick-ass little Aiptek/Mustek mini-digital camcorders (make sure you get one with A/V inputs) and hook up a Sony bulletcam in the front bumper for legit footage.

Have you considered a brake proportioning valve to dial that shit in... I think FM is having a sale on one of theirs.

I don't see mention of a blow-off-valve or catch-can.

Sam: I actually got in the group buy on those adjusters. Not a bad deal at all, and if it helps just a little, it is money well spent. I am running RX7 460cc injectors on it. 200hp would be really ideal for the car in my mind. Any more and i risk needing a 6-speed to handle the abuse the track can give it.

For right now i am going to running my car at Texas World Speedway in College Station, TX (Whoop!) and probably at Motorsports Ranch in Houston. At TWS, there is a pretty good stretch of straight about 1/2 mile long. I am not looking to be ultra competative yet. Really i am looking to just learn more about how to race, how to understand the limits of a car, and what it takes to raise the limits. I am not one to be able to learn any of that without actually doing it. The basics i have, but i have A LOT to learn before being ultra competative.

I thought that the gears that were on the torsen type I were 4.1. Am i wrong?

Blow off valve i thought of, but not the catch can. Need to see how people have done theirs in the past.

that's what I meant by beefing up the pcv system. It will stop keeping oil in the engine, it starts thinking the intercooler is an oil sump tank. Look at fm's track dog, they ran an oil sump system

You can use nylon straps to the stock hooks, as long as they are rated enough and extend out of the body work. A friend of mine welds coils he cut from stock springs to the factory hooks for his tow hooks.

The seat back brace will depend on what seat you get and how it's mounted. You can make one easy enough, you just need to tie the back of the seat to the roll cage. If the seat is not current FIA and mounted in accordance to the FIA.



Sounds like a winner. Keep in mind with the carbotechs you can swap compounds at will, as long as you stick with the carbs.

Thanks ben. When i start doing this, i will try to make something like what they did with the Targa Miata site. I am going to strip everything off of this car and make it better than new. I have space at work and a lot of down time now, so i can really focus on this until things pick up again. Hopefully i can get about 4 hours a day in on it for a couple weeks, maybe a month.